Chilli peppers belong to Capsicum, a genus of the nightshade family. Horticulturists consider them to be fruits. Most chillis contain capsaicin, an alkaloid compound that binds to pain receptors on the tongue, producing a sensation of burning. Chilli peppers are widely used in many cuisines as a spice to add "heat" to dishes.
The Scoville scale is a measurement of the spiciness or heat of chilli peppers and other spicy foods. It is based on the concentration of capsaicinoids, particularly capsaicin, which is the active component that produces the sensation of heat. The scale is named after its creator, Wilbur Scoville, an American pharmacist who developed it in 1912.
The Scoville Heat Unit (SHU) is used to quantify how many times an exact weight of dried pepper dissolved in alcohol must be diluted in sugar water until its heat is no longer detectable by a majority (at least three) of a panel of five trained tasters. The heat level is based on this dilution, rated in multiples of 100 SHU. The higher the SHU, the hotter the pepper.
Examples of chillis on the Scoville scale:
- Bell Pepper: 0 SHU
- Poblano Pepper: 1,000–2,000 SHU
- Jalapeño Pepper: 2,500–8,000 SHU
- Cayenne Pepper: 30,000–50,000 SHU
- Habanero Pepper: 100,000–350,000 SHU
- Ghost Pepper (Bhut Jolokia): 800,000–1,041,427 SHU
- Carolina Reaper: 1,400,000–2,200,000 SHU (Guinness World Record from 2017–2023)
- Pepper X: 2,600,000+ (Guinness World Record since 2023)
The weakness of this so-called Scoville “organoleptic test” is its imprecision due to human subjectivity, depending on the taster's palate and number of mouth heat receptors, which vary widely among subjects. Another shortcoming is sensory fatigue; the palate is quickly desensitised to capsaicinoids after tasting a few samples within a short time period. Results vary widely (up to ± 50%) between laboratories.
As a result, and since the 1980s, spice heat has been assessed quantitatively by high-performance liquid chromatography (HPLC), which measures the concentration of heat-producing capsaicinoids. The results of this test can be converted to Scoville Heat Units by multiplying the parts-per-million by 15.
Three more interesting things about chillis: chillis are believed to have health benefits, four show jumpers were disqualified from the 2008 Olympic Games for having treated their horses with creams containing capsaicin, which can act as a stimulant, traffic cops in China hand out chilis to keep drivers alert. [Ed: Not sure I would trust a driver whose eyes were watering.]
As it happens, there are a lot of people out there who are obsessed with chillis … cross-breeding them, growing them, eating them, making sauces out of them, etc. “Chilliheads” seem to mostly be American, British and Australian men. “Smokin” Ed Currie, the South Carolina hot chilli expert who crossbred and grew a “Carolina Reaper” that’s hotter than most pepper sprays police use to subdue criminals, recently broke his own world record with a chilli that’s three times hotter. “Pepper X” was publicly named the hottest pepper in the world on 9 October 2023 by Guinness World Records.
Finally, since 2015, American YouTuber and host Sean Evans has put an impressive mix of celebrities in the literal hot seat, challenging them to eat increasingly spicy chicken wings and answer probing questions crafted by his research team. You can browse that series HERE.
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References
wikipedia.org/wiki/Hottest_chili_pepper
wikipedia.org/wiki/Scoville_scale
newyorker.com/magazine/2013/11/04/fire-eaters
reddragonseeds.co.uk
onimapantry.com/blogs/blog/understanding-the-scoville-scale-what-you-need-to-know
puckerbuttpeppercompany.com/pages/our-roots
smh.com.au/world/north-america/he-held-the-record-for-hottest-chilli-then-his-pepper-x-scorched-it-20231019
Images
1. Scoville scale
2. Wilbur Lincoln Scoville (1865–1942) devised his test and scale in 1912 while working at the Parke-Davis pharmaceutical company to measure the pungency, "spiciness" or "capsaicin concentration” of various chilli peppers.
3. Pepper stand at Central Market in Houston, Texas, showing its peppers ranked on the Scoville scale
4. The capsaicin "pharmacophore", the portion of the molecule that produces biological effects
5. “Smokin” Ed Currie. Credit: puckerbuttpeppercompany.com
6. Mature Carolina Reaper. Photo credit: Magnolia677
7. Carolina Reaper. Guinness World Record for hottest pepper, 2017–2023
8. Hot Ones host Sean Evans
9. Video Playlist: Hot Ones by First We Feast on YouTube
